1. Field of the Invention
The present invention relates to fittings for connecting beams to columns of a steel frame construction and a reinforced concrete steel frame construction, particularly for connecting H-shaped steel beams to columns having open crosssections and a method of connecting beams to columns of a steel frame construction by means of the fittings.
It will be understood that the term "fitting" used herein means the metallic integral article according to the present invention while the term "fitting member" means also the same article but is used to indicate the difference in shape of the fitting such as "outer fitting member" or "inner fitting member".
2. Description of the Prior Art
Heretofore, to connect a beam to a column of a steel frame construction, it has been known to provide T-shaped members of which protrusions are connected to flanges of the beam by means of high strength bolts with one surface frictional engagement, and of which bottom plates are connected to a flange of the column by means of high strength bolts under tensile forces, a joint member connecting a web of the beam and the flange of the column, and horizontal stiffeners fixed to the column at the locations of the T-shaped members. However, since the thickness of the bottom plate of the T-shaped member is so uniform that when the flange of the beam is subjected to a tensile force, the bolts connecting the bottom plate to the flange of the column will be additionally subjected to forces resulting from a lever effect due to the shape of the T-shaped member, with the result that the joint efficiency of the connection will be lower. Furthermore, the flange of the beam and the T-shaped member are connected in one surface frictional engagement, so that a number of the bolts are required to obtain a frictional force desired as a joint, which may increase not only labor cost for working the members, columns and beams in a factory fabricating them but also labor cost for assembling them in building site.
In the prior art, moreover, the joint members are required to support shearing forces acting upon the beam. Such joint members may also increase not only the labor cost for working the members, columns and beams in the factory fabricating them but also the labor cost for assembling them in building site.
In case of a connection of a beam to a web of a column, it has been found that when the beam is subjected to a severe bending moment, the web of the column at the connection will be the weakest point and if flanges of the column without web stiffeners are subjected to a bending moment, the distance between the flanges of the column is often increased to a greater extent than in any other connection methods.